clydem

My wife called to say the car was towed & the guy said timing belt is broken. Naturally, I'm out of town.

Is it an interference engine? ie are the valves mashed into the pistons?

zip439

I think the 320 has an M112 engine in it. There is no timing belt on an M112 engine, only the serpentine which is an easy fix. Just put another belt on it and you are good to go. That's the belt you see when looking at the front of the engine behind the radiator. The timing is accomplished with a chain drive run off the crankshaft. All that is internal, you can not see it and seldom ever breaks.

tw2

+1 very uncommon to break the timing chain. Hopefully it is just the accessory belt as above.

clydem

Thank you gentlemen.
A few more calls to the wife confirmed it's probably just the serpentine.
I'll order the belt & idlers from Pelican

PelicanParts.com

If you have any questions or need any help with your order please do not hesitate to let me know.

clydem

Pelican's kit came with the spring loaded tensioner, and two other idlers. Wonderful as one of the idlers (Guide pulley #4) was missing. broken pieces lay about the engine. Who makes idler wheels out of plastic???


anyway, belt strands all over the place! She even got it wrapped around the alternator wheel/pulley. How the heck do I lock the armateurs on the alternator so I can get a socket on the bolt & pull the wheel off?
and/or how do I get the alternator out. I see the two 11mm bolts, it's now free of the block. But how does the electric wires come off? and do you just wiggle it out of it's slot on the corner of the engine?

clydem

I'm still interested in the answer. If you also need a wheel puller too.


I found a thread on Alternator removal and it didn't look fun pulling it from underneath.
But I was lucky in using cheapy Harbor Freight metal picks & picking the wire from around the shaft. Took about 30 min. Getting the alternator back onto its brackets and bolted in took some coaxing with a rubber mallet.


There's a little squeak still. I'm going to let it settle in just in case. But I'm thinking it's one of the new pulleys

insame1

The power wire is held on with a 10mm nut. You need to just twist and turn the alternator till it comes out. It will trust me. As for the pulley I always used a belt and an impact gun. As far as one of the new pulleys making noise did you torque them to the correct spec?

Rudeney

I had the same thing happen on my C240 - shredded belt sucked into the alternator. I was able to remove it from the top (very easy) and just took my time with a knife and needle nose pliers to extract all the belt shards.

clydem

For those that care, Gates K060942 is a replacement. About $40 at your local parts supplier.


20mmx2407mm OC
13/16" x 94 3/4" OC

tw2

I realize we are not talking about the timing chain but since it was brought up, are these engines (M112, M113) interference?

Rudeney

I am fairly certain these are interference engines. But the timing chain should last 500K miles or more. There have been some instance of chain failure on the M271 I4 engines, but it's because it's a single-row chain. Chains are fairly easy to replace on these. You remove the valve/head cover, separate a link, and "draw-in" a new chain.

merceBENZ

Just for the record. How often serpentine belt should be replaced and how long does it take?

sailorben

Both my CLKs have needed changing at 120-130,000
Well not broken, or noisy, but a few cracks on the edges. Takes seconds.

Get a leverage bar/wrench + 17mm socket, lever the tensioner, take old belt off and out the new one on. So incredibly easy to do.

Check your idlers and other pulleys whilst doing so. I have changed the two idlers and tensioner at 120,000, as there was a little bit of rattle in the bearing, not a lot, but I could feel they weren't perfect, so swapped them out. Probably had a fair bit of life left, but I like to be prophylactic.

merceBENZ

How do I wrap around idlers deep down the engine? That is so tight.
PS
Never done it before

mis3

Back in Jan-2013 when my 2004 CLK320 was 166k miles, the local dealership replaced my serpentine belt due to small cracks on the belt. The idler pulley, belt tensioner pulley and crank shift pulley were replaced at the same time.

2004 CLK has the M112/722.6 configuration. Is my timing chain single-row or double-row chain? My car now has 220k miles and I am wondering if I should replace the timing chain.

Rudeney

Here's the belt routing diagram:

http://benzbits.com/M112/BeltRouting.pdf

While there is not much room to get your hands in there on the V8 engine, it is possible. The tensioner pulley housing is spring loaded. There is a "dead nut" (basically a hex nut welded in place) on the spring housing that you attach a socket to and pull on it to move the tensioner pulley, thus releasing pressure on the belt. There is also a hole in the spring housing where you can insert a small screwdriver to hold it "open" while working on the belt.

merceBENZ

That is a brilliant explanation! Thank you for file as well. However, I can't get what are you trying to say here: There is also a hole in the spring housing where you can insert a small screwdriver to hold it "open" while working on the belt. Could you explain here, please?

sailorben

So when you lever the outer moving tensioner piece back, there is a hole in there, which when leant back far enough, will align with a hole on the body of the tensioner. Thus allowing you to slot an Allen key or screw driver through the aligned holes to keep the tensioner held down.

merceBENZ

Thank you for clarifying.